blob: 56fb26127fef2544c52838674b2e8b84ae873807 [file] [log] [blame]
Joel Becker7063fbf2005-12-15 14:29:43 -08001/* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
3 *
4 * dir.c - Operations for configfs directories.
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public
17 * License along with this program; if not, write to the
18 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 * Boston, MA 021110-1307, USA.
20 *
21 * Based on sysfs:
22 * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
23 *
24 * configfs Copyright (C) 2005 Oracle. All rights reserved.
25 */
26
27#undef DEBUG
28
29#include <linux/fs.h>
30#include <linux/mount.h>
31#include <linux/module.h>
32#include <linux/slab.h>
Louis Rilling107ed402008-06-16 19:01:00 +020033#include <linux/err.h>
Joel Becker7063fbf2005-12-15 14:29:43 -080034
35#include <linux/configfs.h>
36#include "configfs_internal.h"
37
38DECLARE_RWSEM(configfs_rename_sem);
Louis Rilling6f610762008-06-16 19:00:58 +020039/*
40 * Protects mutations of configfs_dirent linkage together with proper i_mutex
Louis Rilling5301a772008-06-16 19:00:59 +020041 * Also protects mutations of symlinks linkage to target configfs_dirent
Louis Rilling6f610762008-06-16 19:00:58 +020042 * Mutators of configfs_dirent linkage must *both* have the proper inode locked
43 * and configfs_dirent_lock locked, in that order.
Louis Rilling5301a772008-06-16 19:00:59 +020044 * This allows one to safely traverse configfs_dirent trees and symlinks without
45 * having to lock inodes.
Louis Rillingb3e76af2008-06-16 19:01:01 +020046 *
47 * Protects setting of CONFIGFS_USET_DROPPING: checking the flag
48 * unlocked is not reliable unless in detach_groups() called from
49 * rmdir()/unregister() and from configfs_attach_group()
Louis Rilling6f610762008-06-16 19:00:58 +020050 */
51DEFINE_SPINLOCK(configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -080052
53static void configfs_d_iput(struct dentry * dentry,
54 struct inode * inode)
55{
Joel Becker24307aa2011-05-18 04:08:16 -070056 struct configfs_dirent *sd = dentry->d_fsdata;
Joel Becker7063fbf2005-12-15 14:29:43 -080057
58 if (sd) {
Joel Becker24307aa2011-05-18 04:08:16 -070059 /* Coordinate with configfs_readdir */
60 spin_lock(&configfs_dirent_lock);
Junxiao Bi76ae2812013-11-21 14:31:56 -080061 /* Coordinate with configfs_attach_attr where will increase
62 * sd->s_count and update sd->s_dentry to new allocated one.
63 * Only set sd->dentry to null when this dentry is the only
64 * sd owner.
65 * If not do so, configfs_d_iput may run just after
66 * configfs_attach_attr and set sd->s_dentry to null
67 * even it's still in use.
68 */
69 if (atomic_read(&sd->s_count) <= 2)
70 sd->s_dentry = NULL;
71
Joel Becker24307aa2011-05-18 04:08:16 -070072 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -080073 configfs_put(sd);
74 }
75 iput(inode);
76}
77
Al Virod463a0c2011-01-12 16:41:05 -050078const struct dentry_operations configfs_dentry_ops = {
Joel Becker7063fbf2005-12-15 14:29:43 -080079 .d_iput = configfs_d_iput,
Al Virob26d4cd2013-10-25 18:47:37 -040080 .d_delete = always_delete_dentry,
Joel Becker7063fbf2005-12-15 14:29:43 -080081};
82
Louis Rillinge74cc062009-01-28 19:18:32 +010083#ifdef CONFIG_LOCKDEP
84
85/*
86 * Helpers to make lockdep happy with our recursive locking of default groups'
87 * inodes (see configfs_attach_group() and configfs_detach_group()).
88 * We put default groups i_mutexes in separate classes according to their depth
89 * from the youngest non-default group ancestor.
90 *
91 * For a non-default group A having default groups A/B, A/C, and A/C/D, default
92 * groups A/B and A/C will have their inode's mutex in class
93 * default_group_class[0], and default group A/C/D will be in
94 * default_group_class[1].
95 *
96 * The lock classes are declared and assigned in inode.c, according to the
97 * s_depth value.
98 * The s_depth value is initialized to -1, adjusted to >= 0 when attaching
99 * default groups, and reset to -1 when all default groups are attached. During
100 * attachment, if configfs_create() sees s_depth > 0, the lock class of the new
101 * inode's mutex is set to default_group_class[s_depth - 1].
102 */
103
104static void configfs_init_dirent_depth(struct configfs_dirent *sd)
105{
106 sd->s_depth = -1;
107}
108
109static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd,
110 struct configfs_dirent *sd)
111{
112 int parent_depth = parent_sd->s_depth;
113
114 if (parent_depth >= 0)
115 sd->s_depth = parent_depth + 1;
116}
117
118static void
119configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd)
120{
121 /*
122 * item's i_mutex class is already setup, so s_depth is now only
123 * used to set new sub-directories s_depth, which is always done
124 * with item's i_mutex locked.
125 */
126 /*
127 * sd->s_depth == -1 iff we are a non default group.
128 * else (we are a default group) sd->s_depth > 0 (see
129 * create_dir()).
130 */
131 if (sd->s_depth == -1)
132 /*
133 * We are a non default group and we are going to create
134 * default groups.
135 */
136 sd->s_depth = 0;
137}
138
139static void
140configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd)
141{
142 /* We will not create default groups anymore. */
143 sd->s_depth = -1;
144}
145
146#else /* CONFIG_LOCKDEP */
147
148static void configfs_init_dirent_depth(struct configfs_dirent *sd)
149{
150}
151
152static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd,
153 struct configfs_dirent *sd)
154{
155}
156
157static void
158configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd)
159{
160}
161
162static void
163configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd)
164{
165}
166
167#endif /* CONFIG_LOCKDEP */
168
Joel Becker7063fbf2005-12-15 14:29:43 -0800169/*
170 * Allocates a new configfs_dirent and links it to the parent configfs_dirent
171 */
Louis Rilling420118c2009-01-28 19:18:33 +0100172static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *parent_sd,
173 void *element, int type)
Joel Becker7063fbf2005-12-15 14:29:43 -0800174{
175 struct configfs_dirent * sd;
176
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800177 sd = kmem_cache_zalloc(configfs_dir_cachep, GFP_KERNEL);
Joel Becker7063fbf2005-12-15 14:29:43 -0800178 if (!sd)
Louis Rilling107ed402008-06-16 19:01:00 +0200179 return ERR_PTR(-ENOMEM);
Joel Becker7063fbf2005-12-15 14:29:43 -0800180
Joel Becker7063fbf2005-12-15 14:29:43 -0800181 atomic_set(&sd->s_count, 1);
182 INIT_LIST_HEAD(&sd->s_links);
183 INIT_LIST_HEAD(&sd->s_children);
Joel Becker7063fbf2005-12-15 14:29:43 -0800184 sd->s_element = element;
Louis Rilling420118c2009-01-28 19:18:33 +0100185 sd->s_type = type;
Louis Rillinge74cc062009-01-28 19:18:32 +0100186 configfs_init_dirent_depth(sd);
Louis Rilling6f610762008-06-16 19:00:58 +0200187 spin_lock(&configfs_dirent_lock);
Louis Rillingb3e76af2008-06-16 19:01:01 +0200188 if (parent_sd->s_type & CONFIGFS_USET_DROPPING) {
189 spin_unlock(&configfs_dirent_lock);
190 kmem_cache_free(configfs_dir_cachep, sd);
191 return ERR_PTR(-ENOENT);
192 }
Louis Rilling6f610762008-06-16 19:00:58 +0200193 list_add(&sd->s_sibling, &parent_sd->s_children);
194 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800195
196 return sd;
197}
198
Joel Beckerb4c98f62006-09-13 11:01:19 -0700199/*
200 *
201 * Return -EEXIST if there is already a configfs element with the same
202 * name for the same parent.
203 *
204 * called with parent inode's i_mutex held
205 */
Adrian Bunk58d206c2006-11-20 03:24:00 +0100206static int configfs_dirent_exists(struct configfs_dirent *parent_sd,
207 const unsigned char *new)
Joel Beckerb4c98f62006-09-13 11:01:19 -0700208{
209 struct configfs_dirent * sd;
210
211 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
212 if (sd->s_element) {
213 const unsigned char *existing = configfs_get_name(sd);
214 if (strcmp(existing, new))
215 continue;
216 else
217 return -EEXIST;
218 }
219 }
220
221 return 0;
222}
223
224
Joel Becker7063fbf2005-12-15 14:29:43 -0800225int configfs_make_dirent(struct configfs_dirent * parent_sd,
226 struct dentry * dentry, void * element,
227 umode_t mode, int type)
228{
229 struct configfs_dirent * sd;
230
Louis Rilling420118c2009-01-28 19:18:33 +0100231 sd = configfs_new_dirent(parent_sd, element, type);
Louis Rilling107ed402008-06-16 19:01:00 +0200232 if (IS_ERR(sd))
233 return PTR_ERR(sd);
Joel Becker7063fbf2005-12-15 14:29:43 -0800234
235 sd->s_mode = mode;
Joel Becker7063fbf2005-12-15 14:29:43 -0800236 sd->s_dentry = dentry;
Nick Pigginfbc8d4c02011-01-07 17:49:21 +1100237 if (dentry)
Joel Becker7063fbf2005-12-15 14:29:43 -0800238 dentry->d_fsdata = configfs_get(sd);
Joel Becker7063fbf2005-12-15 14:29:43 -0800239
240 return 0;
241}
242
Al Viroc88b1e72015-01-29 00:17:57 -0500243static void init_dir(struct inode * inode)
Joel Becker7063fbf2005-12-15 14:29:43 -0800244{
245 inode->i_op = &configfs_dir_inode_operations;
246 inode->i_fop = &configfs_dir_operations;
247
248 /* directory inodes start off with i_nlink == 2 (for "." entry) */
Dave Hansend8c76e62006-09-30 23:29:04 -0700249 inc_nlink(inode);
Joel Becker7063fbf2005-12-15 14:29:43 -0800250}
251
Al Viroc88b1e72015-01-29 00:17:57 -0500252static void configfs_init_file(struct inode * inode)
Joel Becker7063fbf2005-12-15 14:29:43 -0800253{
254 inode->i_size = PAGE_SIZE;
255 inode->i_fop = &configfs_file_operations;
Joel Becker7063fbf2005-12-15 14:29:43 -0800256}
257
Pantelis Antoniou03607ac2015-10-22 23:30:04 +0300258static void configfs_init_bin_file(struct inode *inode)
259{
260 inode->i_size = 0;
261 inode->i_fop = &configfs_bin_file_operations;
262}
263
Al Viroc88b1e72015-01-29 00:17:57 -0500264static void init_symlink(struct inode * inode)
Joel Becker7063fbf2005-12-15 14:29:43 -0800265{
266 inode->i_op = &configfs_symlink_inode_operations;
Joel Becker7063fbf2005-12-15 14:29:43 -0800267}
268
Joel Becker7063fbf2005-12-15 14:29:43 -0800269/**
270 * configfs_create_dir - create a directory for an config_item.
271 * @item: config_itemwe're creating directory for.
272 * @dentry: config_item's dentry.
Louis Rilling2a109f22008-07-04 16:56:05 +0200273 *
274 * Note: user-created entries won't be allowed under this new directory
275 * until it is validated by configfs_dir_set_ready()
Joel Becker7063fbf2005-12-15 14:29:43 -0800276 */
277
Al Viro1cf97d02015-01-29 00:20:49 -0500278static int configfs_create_dir(struct config_item *item, struct dentry *dentry)
Joel Becker7063fbf2005-12-15 14:29:43 -0800279{
Al Viro1cf97d02015-01-29 00:20:49 -0500280 int error;
281 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
282 struct dentry *p = dentry->d_parent;
283
284 BUG_ON(!item);
285
286 error = configfs_dirent_exists(p->d_fsdata, dentry->d_name.name);
287 if (unlikely(error))
288 return error;
289
290 error = configfs_make_dirent(p->d_fsdata, dentry, item, mode,
291 CONFIGFS_DIR | CONFIGFS_USET_CREATING);
292 if (unlikely(error))
293 return error;
294
295 configfs_set_dir_dirent_depth(p->d_fsdata, dentry->d_fsdata);
296 error = configfs_create(dentry, mode, init_dir);
297 if (!error) {
David Howells2b0143b2015-03-17 22:25:59 +0000298 inc_nlink(d_inode(p));
Joel Becker7063fbf2005-12-15 14:29:43 -0800299 item->ci_dentry = dentry;
Al Viro1cf97d02015-01-29 00:20:49 -0500300 } else {
301 struct configfs_dirent *sd = dentry->d_fsdata;
302 if (sd) {
303 spin_lock(&configfs_dirent_lock);
304 list_del_init(&sd->s_sibling);
305 spin_unlock(&configfs_dirent_lock);
306 configfs_put(sd);
307 }
308 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800309 return error;
310}
311
Louis Rilling2a109f22008-07-04 16:56:05 +0200312/*
313 * Allow userspace to create new entries under a new directory created with
314 * configfs_create_dir(), and under all of its chidlren directories recursively.
315 * @sd configfs_dirent of the new directory to validate
316 *
317 * Caller must hold configfs_dirent_lock.
318 */
319static void configfs_dir_set_ready(struct configfs_dirent *sd)
320{
321 struct configfs_dirent *child_sd;
322
323 sd->s_type &= ~CONFIGFS_USET_CREATING;
324 list_for_each_entry(child_sd, &sd->s_children, s_sibling)
325 if (child_sd->s_type & CONFIGFS_USET_CREATING)
326 configfs_dir_set_ready(child_sd);
327}
328
329/*
330 * Check that a directory does not belong to a directory hierarchy being
331 * attached and not validated yet.
332 * @sd configfs_dirent of the directory to check
333 *
334 * @return non-zero iff the directory was validated
335 *
336 * Note: takes configfs_dirent_lock, so the result may change from false to true
337 * in two consecutive calls, but never from true to false.
338 */
339int configfs_dirent_is_ready(struct configfs_dirent *sd)
340{
341 int ret;
342
343 spin_lock(&configfs_dirent_lock);
344 ret = !(sd->s_type & CONFIGFS_USET_CREATING);
345 spin_unlock(&configfs_dirent_lock);
346
347 return ret;
348}
349
Joel Becker7063fbf2005-12-15 14:29:43 -0800350int configfs_create_link(struct configfs_symlink *sl,
351 struct dentry *parent,
352 struct dentry *dentry)
353{
354 int err = 0;
355 umode_t mode = S_IFLNK | S_IRWXUGO;
356
Joel Becker3d0f89b2006-01-25 13:31:07 -0800357 err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode,
358 CONFIGFS_ITEM_LINK);
Joel Becker7063fbf2005-12-15 14:29:43 -0800359 if (!err) {
Joel Becker3d0f89b2006-01-25 13:31:07 -0800360 err = configfs_create(dentry, mode, init_symlink);
Nick Pigginfbc8d4c02011-01-07 17:49:21 +1100361 if (err) {
Joel Becker3d0f89b2006-01-25 13:31:07 -0800362 struct configfs_dirent *sd = dentry->d_fsdata;
363 if (sd) {
Louis Rilling6f610762008-06-16 19:00:58 +0200364 spin_lock(&configfs_dirent_lock);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800365 list_del_init(&sd->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +0200366 spin_unlock(&configfs_dirent_lock);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800367 configfs_put(sd);
368 }
369 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800370 }
371 return err;
372}
373
374static void remove_dir(struct dentry * d)
375{
376 struct dentry * parent = dget(d->d_parent);
377 struct configfs_dirent * sd;
378
379 sd = d->d_fsdata;
Louis Rilling6f610762008-06-16 19:00:58 +0200380 spin_lock(&configfs_dirent_lock);
Joel Beckere7515d02006-03-10 11:42:30 -0800381 list_del_init(&sd->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +0200382 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800383 configfs_put(sd);
David Howells2b0143b2015-03-17 22:25:59 +0000384 if (d_really_is_positive(d))
385 simple_rmdir(d_inode(parent),d);
Joel Becker7063fbf2005-12-15 14:29:43 -0800386
Al Viroa4555892014-10-21 20:11:25 -0400387 pr_debug(" o %pd removing done (%d)\n", d, d_count(d));
Joel Becker7063fbf2005-12-15 14:29:43 -0800388
389 dput(parent);
390}
391
392/**
393 * configfs_remove_dir - remove an config_item's directory.
394 * @item: config_item we're removing.
395 *
396 * The only thing special about this is that we remove any files in
397 * the directory before we remove the directory, and we've inlined
398 * what used to be configfs_rmdir() below, instead of calling separately.
Louis Rilling2e2ce172008-07-04 16:56:06 +0200399 *
400 * Caller holds the mutex of the item's inode
Joel Becker7063fbf2005-12-15 14:29:43 -0800401 */
402
403static void configfs_remove_dir(struct config_item * item)
404{
405 struct dentry * dentry = dget(item->ci_dentry);
406
407 if (!dentry)
408 return;
409
410 remove_dir(dentry);
411 /**
412 * Drop reference from dget() on entrance.
413 */
414 dput(dentry);
415}
416
417
418/* attaches attribute's configfs_dirent to the dentry corresponding to the
419 * attribute file
420 */
421static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry)
422{
423 struct configfs_attribute * attr = sd->s_element;
424 int error;
425
Junxiao Bi76ae2812013-11-21 14:31:56 -0800426 spin_lock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800427 dentry->d_fsdata = configfs_get(sd);
428 sd->s_dentry = dentry;
Junxiao Bi76ae2812013-11-21 14:31:56 -0800429 spin_unlock(&configfs_dirent_lock);
430
Dave Hansence8d2cd2007-10-16 23:31:13 -0700431 error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG,
Pantelis Antoniou03607ac2015-10-22 23:30:04 +0300432 (sd->s_type & CONFIGFS_ITEM_BIN_ATTR) ?
433 configfs_init_bin_file :
434 configfs_init_file);
Al Viro5cf3b562016-03-07 14:25:46 -0500435 if (error)
Joel Becker3d0f89b2006-01-25 13:31:07 -0800436 configfs_put(sd);
Al Viro5cf3b562016-03-07 14:25:46 -0500437 return error;
Joel Becker7063fbf2005-12-15 14:29:43 -0800438}
439
440static struct dentry * configfs_lookup(struct inode *dir,
441 struct dentry *dentry,
Al Viro00cd8dd2012-06-10 17:13:09 -0400442 unsigned int flags)
Joel Becker7063fbf2005-12-15 14:29:43 -0800443{
444 struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
445 struct configfs_dirent * sd;
446 int found = 0;
Louis Rilling2a109f22008-07-04 16:56:05 +0200447 int err;
448
449 /*
450 * Fake invisibility if dir belongs to a group/default groups hierarchy
451 * being attached
452 *
453 * This forbids userspace to read/write attributes of items which may
454 * not complete their initialization, since the dentries of the
455 * attributes won't be instantiated.
456 */
457 err = -ENOENT;
458 if (!configfs_dirent_is_ready(parent_sd))
459 goto out;
Joel Becker7063fbf2005-12-15 14:29:43 -0800460
461 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
462 if (sd->s_type & CONFIGFS_NOT_PINNED) {
463 const unsigned char * name = configfs_get_name(sd);
464
465 if (strcmp(name, dentry->d_name.name))
466 continue;
467
468 found = 1;
469 err = configfs_attach_attr(sd, dentry);
470 break;
471 }
472 }
473
474 if (!found) {
475 /*
476 * If it doesn't exist and it isn't a NOT_PINNED item,
477 * it must be negative.
478 */
Nick Pigginfbc8d4c02011-01-07 17:49:21 +1100479 if (dentry->d_name.len > NAME_MAX)
480 return ERR_PTR(-ENAMETOOLONG);
Nick Pigginfbc8d4c02011-01-07 17:49:21 +1100481 d_add(dentry, NULL);
482 return NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -0800483 }
484
Louis Rilling2a109f22008-07-04 16:56:05 +0200485out:
Joel Becker7063fbf2005-12-15 14:29:43 -0800486 return ERR_PTR(err);
487}
488
489/*
490 * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are
Louis Rillingb3e76af2008-06-16 19:01:01 +0200491 * attributes and are removed by rmdir(). We recurse, setting
492 * CONFIGFS_USET_DROPPING on all children that are candidates for
493 * default detach.
494 * If there is an error, the caller will reset the flags via
495 * configfs_detach_rollback().
Joel Becker7063fbf2005-12-15 14:29:43 -0800496 */
Al Viro48f35b72016-04-12 00:37:59 -0400497static int configfs_detach_prep(struct dentry *dentry, struct dentry **wait)
Joel Becker7063fbf2005-12-15 14:29:43 -0800498{
499 struct configfs_dirent *parent_sd = dentry->d_fsdata;
500 struct configfs_dirent *sd;
501 int ret;
502
Louis Rilling4768e9b2008-06-23 14:16:17 +0200503 /* Mark that we're trying to drop the group */
504 parent_sd->s_type |= CONFIGFS_USET_DROPPING;
505
Joel Becker7063fbf2005-12-15 14:29:43 -0800506 ret = -EBUSY;
507 if (!list_empty(&parent_sd->s_links))
508 goto out;
509
510 ret = 0;
511 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
Louis Rilling99cefda2008-06-27 13:10:25 +0200512 if (!sd->s_element ||
513 (sd->s_type & CONFIGFS_NOT_PINNED))
Joel Becker7063fbf2005-12-15 14:29:43 -0800514 continue;
515 if (sd->s_type & CONFIGFS_USET_DEFAULT) {
Louis Rilling6d8344b2008-06-16 19:01:02 +0200516 /* Abort if racing with mkdir() */
517 if (sd->s_type & CONFIGFS_USET_IN_MKDIR) {
Al Viro48f35b72016-04-12 00:37:59 -0400518 if (wait)
519 *wait= dget(sd->s_dentry);
Louis Rilling6d8344b2008-06-16 19:01:02 +0200520 return -EAGAIN;
521 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800522
Joel Becker631d1fe2007-06-18 18:06:09 -0700523 /*
524 * Yup, recursive. If there's a problem, blame
525 * deep nesting of default_groups
526 */
Al Viro48f35b72016-04-12 00:37:59 -0400527 ret = configfs_detach_prep(sd->s_dentry, wait);
Joel Becker7063fbf2005-12-15 14:29:43 -0800528 if (!ret)
Joel Beckere7515d02006-03-10 11:42:30 -0800529 continue;
Joel Becker7063fbf2005-12-15 14:29:43 -0800530 } else
531 ret = -ENOTEMPTY;
532
533 break;
534 }
535
536out:
537 return ret;
538}
539
540/*
Louis Rillingb3e76af2008-06-16 19:01:01 +0200541 * Walk the tree, resetting CONFIGFS_USET_DROPPING wherever it was
Joel Becker7063fbf2005-12-15 14:29:43 -0800542 * set.
543 */
544static void configfs_detach_rollback(struct dentry *dentry)
545{
546 struct configfs_dirent *parent_sd = dentry->d_fsdata;
547 struct configfs_dirent *sd;
548
Louis Rilling4768e9b2008-06-23 14:16:17 +0200549 parent_sd->s_type &= ~CONFIGFS_USET_DROPPING;
550
551 list_for_each_entry(sd, &parent_sd->s_children, s_sibling)
552 if (sd->s_type & CONFIGFS_USET_DEFAULT)
Joel Becker7063fbf2005-12-15 14:29:43 -0800553 configfs_detach_rollback(sd->s_dentry);
Joel Becker7063fbf2005-12-15 14:29:43 -0800554}
555
556static void detach_attrs(struct config_item * item)
557{
558 struct dentry * dentry = dget(item->ci_dentry);
559 struct configfs_dirent * parent_sd;
560 struct configfs_dirent * sd, * tmp;
561
562 if (!dentry)
563 return;
564
565 pr_debug("configfs %s: dropping attrs for dir\n",
566 dentry->d_name.name);
567
568 parent_sd = dentry->d_fsdata;
569 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
570 if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED))
571 continue;
Louis Rilling6f610762008-06-16 19:00:58 +0200572 spin_lock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800573 list_del_init(&sd->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +0200574 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800575 configfs_drop_dentry(sd, dentry);
576 configfs_put(sd);
577 }
578
579 /**
580 * Drop reference from dget() on entrance.
581 */
582 dput(dentry);
583}
584
585static int populate_attrs(struct config_item *item)
586{
587 struct config_item_type *t = item->ci_type;
588 struct configfs_attribute *attr;
Pantelis Antoniou03607ac2015-10-22 23:30:04 +0300589 struct configfs_bin_attribute *bin_attr;
Joel Becker7063fbf2005-12-15 14:29:43 -0800590 int error = 0;
591 int i;
592
593 if (!t)
594 return -EINVAL;
595 if (t->ct_attrs) {
596 for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) {
597 if ((error = configfs_create_file(item, attr)))
598 break;
599 }
600 }
Pantelis Antoniou03607ac2015-10-22 23:30:04 +0300601 if (t->ct_bin_attrs) {
602 for (i = 0; (bin_attr = t->ct_bin_attrs[i]) != NULL; i++) {
603 error = configfs_create_bin_file(item, bin_attr);
604 if (error)
605 break;
606 }
607 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800608
609 if (error)
610 detach_attrs(item);
611
612 return error;
613}
614
615static int configfs_attach_group(struct config_item *parent_item,
616 struct config_item *item,
617 struct dentry *dentry);
618static void configfs_detach_group(struct config_item *item);
619
620static void detach_groups(struct config_group *group)
621{
622 struct dentry * dentry = dget(group->cg_item.ci_dentry);
623 struct dentry *child;
624 struct configfs_dirent *parent_sd;
625 struct configfs_dirent *sd, *tmp;
626
627 if (!dentry)
628 return;
629
630 parent_sd = dentry->d_fsdata;
631 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
632 if (!sd->s_element ||
633 !(sd->s_type & CONFIGFS_USET_DEFAULT))
634 continue;
635
636 child = sd->s_dentry;
637
Al Viro59551022016-01-22 15:40:57 -0500638 inode_lock(d_inode(child));
Louis Rillingb3e76af2008-06-16 19:01:01 +0200639
Joel Becker7063fbf2005-12-15 14:29:43 -0800640 configfs_detach_group(sd->s_element);
David Howells2b0143b2015-03-17 22:25:59 +0000641 d_inode(child)->i_flags |= S_DEAD;
Al Virod83c49f2010-04-30 17:17:09 -0400642 dont_mount(child);
Joel Becker7063fbf2005-12-15 14:29:43 -0800643
Al Viro59551022016-01-22 15:40:57 -0500644 inode_unlock(d_inode(child));
Joel Becker7063fbf2005-12-15 14:29:43 -0800645
646 d_delete(child);
647 dput(child);
648 }
649
650 /**
651 * Drop reference from dget() on entrance.
652 */
653 dput(dentry);
654}
655
656/*
657 * This fakes mkdir(2) on a default_groups[] entry. It
658 * creates a dentry, attachs it, and then does fixup
659 * on the sd->s_type.
660 *
661 * We could, perhaps, tweak our parent's ->mkdir for a minute and
662 * try using vfs_mkdir. Just a thought.
663 */
664static int create_default_group(struct config_group *parent_group,
665 struct config_group *group)
666{
667 int ret;
Joel Becker7063fbf2005-12-15 14:29:43 -0800668 struct configfs_dirent *sd;
669 /* We trust the caller holds a reference to parent */
670 struct dentry *child, *parent = parent_group->cg_item.ci_dentry;
671
672 if (!group->cg_item.ci_name)
673 group->cg_item.ci_name = group->cg_item.ci_namebuf;
Joel Becker7063fbf2005-12-15 14:29:43 -0800674
675 ret = -ENOMEM;
Al Viroec193cf2013-07-14 17:16:52 +0400676 child = d_alloc_name(parent, group->cg_item.ci_name);
Joel Becker7063fbf2005-12-15 14:29:43 -0800677 if (child) {
678 d_add(child, NULL);
679
680 ret = configfs_attach_group(&parent_group->cg_item,
681 &group->cg_item, child);
682 if (!ret) {
683 sd = child->d_fsdata;
684 sd->s_type |= CONFIGFS_USET_DEFAULT;
685 } else {
David Howells2b0143b2015-03-17 22:25:59 +0000686 BUG_ON(d_inode(child));
Joel Beckerdf7f9962011-02-22 01:09:49 -0800687 d_drop(child);
Joel Becker7063fbf2005-12-15 14:29:43 -0800688 dput(child);
689 }
690 }
691
692 return ret;
693}
694
695static int populate_groups(struct config_group *group)
696{
697 struct config_group *new_group;
Joel Becker7063fbf2005-12-15 14:29:43 -0800698 int ret = 0;
Joel Becker7063fbf2005-12-15 14:29:43 -0800699
Christoph Hellwig1ae16022016-02-26 11:02:14 +0100700 list_for_each_entry(new_group, &group->default_groups, group_entry) {
701 ret = create_default_group(group, new_group);
702 if (ret) {
703 detach_groups(group);
704 break;
Joel Becker7063fbf2005-12-15 14:29:43 -0800705 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800706 }
707
Joel Becker7063fbf2005-12-15 14:29:43 -0800708 return ret;
709}
710
Christoph Hellwig1ae16022016-02-26 11:02:14 +0100711void configfs_remove_default_groups(struct config_group *group)
712{
713 struct config_group *g, *n;
714
715 list_for_each_entry_safe(g, n, &group->default_groups, group_entry) {
716 list_del(&g->group_entry);
717 config_item_put(&g->cg_item);
718 }
719}
720EXPORT_SYMBOL(configfs_remove_default_groups);
721
Joel Becker7063fbf2005-12-15 14:29:43 -0800722/*
723 * All of link_obj/unlink_obj/link_group/unlink_group require that
Joel Beckere6bd07a2007-07-06 23:33:17 -0700724 * subsys->su_mutex is held.
Joel Becker7063fbf2005-12-15 14:29:43 -0800725 */
726
727static void unlink_obj(struct config_item *item)
728{
729 struct config_group *group;
730
731 group = item->ci_group;
732 if (group) {
733 list_del_init(&item->ci_entry);
734
735 item->ci_group = NULL;
736 item->ci_parent = NULL;
Joel Beckereed7a0d2006-04-11 21:37:20 -0700737
738 /* Drop the reference for ci_entry */
Joel Becker7063fbf2005-12-15 14:29:43 -0800739 config_item_put(item);
740
Joel Beckereed7a0d2006-04-11 21:37:20 -0700741 /* Drop the reference for ci_parent */
Joel Becker7063fbf2005-12-15 14:29:43 -0800742 config_group_put(group);
743 }
744}
745
746static void link_obj(struct config_item *parent_item, struct config_item *item)
747{
Joel Beckereed7a0d2006-04-11 21:37:20 -0700748 /*
749 * Parent seems redundant with group, but it makes certain
750 * traversals much nicer.
751 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800752 item->ci_parent = parent_item;
Joel Beckereed7a0d2006-04-11 21:37:20 -0700753
754 /*
755 * We hold a reference on the parent for the child's ci_parent
756 * link.
757 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800758 item->ci_group = config_group_get(to_config_group(parent_item));
759 list_add_tail(&item->ci_entry, &item->ci_group->cg_children);
760
Joel Beckereed7a0d2006-04-11 21:37:20 -0700761 /*
762 * We hold a reference on the child for ci_entry on the parent's
763 * cg_children
764 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800765 config_item_get(item);
766}
767
768static void unlink_group(struct config_group *group)
769{
Joel Becker7063fbf2005-12-15 14:29:43 -0800770 struct config_group *new_group;
771
Christoph Hellwig1ae16022016-02-26 11:02:14 +0100772 list_for_each_entry(new_group, &group->default_groups, group_entry)
773 unlink_group(new_group);
Joel Becker7063fbf2005-12-15 14:29:43 -0800774
775 group->cg_subsys = NULL;
776 unlink_obj(&group->cg_item);
777}
778
779static void link_group(struct config_group *parent_group, struct config_group *group)
780{
Joel Becker7063fbf2005-12-15 14:29:43 -0800781 struct config_group *new_group;
782 struct configfs_subsystem *subsys = NULL; /* gcc is a turd */
783
784 link_obj(&parent_group->cg_item, &group->cg_item);
785
786 if (parent_group->cg_subsys)
787 subsys = parent_group->cg_subsys;
788 else if (configfs_is_root(&parent_group->cg_item))
789 subsys = to_configfs_subsystem(group);
790 else
791 BUG();
792 group->cg_subsys = subsys;
793
Christoph Hellwig1ae16022016-02-26 11:02:14 +0100794 list_for_each_entry(new_group, &group->default_groups, group_entry)
795 link_group(group, new_group);
Joel Becker7063fbf2005-12-15 14:29:43 -0800796}
797
798/*
799 * The goal is that configfs_attach_item() (and
800 * configfs_attach_group()) can be called from either the VFS or this
801 * module. That is, they assume that the items have been created,
802 * the dentry allocated, and the dcache is all ready to go.
803 *
804 * If they fail, they must clean up after themselves as if they
805 * had never been called. The caller (VFS or local function) will
806 * handle cleaning up the dcache bits.
807 *
808 * configfs_detach_group() and configfs_detach_item() behave similarly on
809 * the way out. They assume that the proper semaphores are held, they
810 * clean up the configfs items, and they expect their callers will
811 * handle the dcache bits.
812 */
813static int configfs_attach_item(struct config_item *parent_item,
814 struct config_item *item,
815 struct dentry *dentry)
816{
817 int ret;
818
819 ret = configfs_create_dir(item, dentry);
820 if (!ret) {
821 ret = populate_attrs(item);
822 if (ret) {
Louis Rilling2e2ce172008-07-04 16:56:06 +0200823 /*
824 * We are going to remove an inode and its dentry but
825 * the VFS may already have hit and used them. Thus,
826 * we must lock them as rmdir() would.
827 */
Al Viro59551022016-01-22 15:40:57 -0500828 inode_lock(d_inode(dentry));
Joel Becker7063fbf2005-12-15 14:29:43 -0800829 configfs_remove_dir(item);
David Howells2b0143b2015-03-17 22:25:59 +0000830 d_inode(dentry)->i_flags |= S_DEAD;
Al Virod83c49f2010-04-30 17:17:09 -0400831 dont_mount(dentry);
Al Viro59551022016-01-22 15:40:57 -0500832 inode_unlock(d_inode(dentry));
Joel Becker7063fbf2005-12-15 14:29:43 -0800833 d_delete(dentry);
834 }
835 }
836
837 return ret;
838}
839
Louis Rilling2e2ce172008-07-04 16:56:06 +0200840/* Caller holds the mutex of the item's inode */
Joel Becker7063fbf2005-12-15 14:29:43 -0800841static void configfs_detach_item(struct config_item *item)
842{
843 detach_attrs(item);
844 configfs_remove_dir(item);
845}
846
847static int configfs_attach_group(struct config_item *parent_item,
848 struct config_item *item,
849 struct dentry *dentry)
850{
851 int ret;
852 struct configfs_dirent *sd;
853
854 ret = configfs_attach_item(parent_item, item, dentry);
855 if (!ret) {
856 sd = dentry->d_fsdata;
857 sd->s_type |= CONFIGFS_USET_DIR;
858
Louis Rilling2e2ce172008-07-04 16:56:06 +0200859 /*
860 * FYI, we're faking mkdir in populate_groups()
861 * We must lock the group's inode to avoid races with the VFS
862 * which can already hit the inode and try to add/remove entries
863 * under it.
864 *
865 * We must also lock the inode to remove it safely in case of
866 * error, as rmdir() would.
867 */
Al Viro59551022016-01-22 15:40:57 -0500868 inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
Louis Rillinge74cc062009-01-28 19:18:32 +0100869 configfs_adjust_dir_dirent_depth_before_populate(sd);
Joel Becker7063fbf2005-12-15 14:29:43 -0800870 ret = populate_groups(to_config_group(item));
871 if (ret) {
872 configfs_detach_item(item);
David Howells2b0143b2015-03-17 22:25:59 +0000873 d_inode(dentry)->i_flags |= S_DEAD;
Al Virod83c49f2010-04-30 17:17:09 -0400874 dont_mount(dentry);
Joel Becker7063fbf2005-12-15 14:29:43 -0800875 }
Louis Rillinge74cc062009-01-28 19:18:32 +0100876 configfs_adjust_dir_dirent_depth_after_populate(sd);
Al Viro59551022016-01-22 15:40:57 -0500877 inode_unlock(d_inode(dentry));
Louis Rilling2e2ce172008-07-04 16:56:06 +0200878 if (ret)
879 d_delete(dentry);
Joel Becker7063fbf2005-12-15 14:29:43 -0800880 }
881
882 return ret;
883}
884
Louis Rilling2e2ce172008-07-04 16:56:06 +0200885/* Caller holds the mutex of the group's inode */
Joel Becker7063fbf2005-12-15 14:29:43 -0800886static void configfs_detach_group(struct config_item *item)
887{
888 detach_groups(to_config_group(item));
889 configfs_detach_item(item);
890}
891
892/*
Joel Becker299894c2006-10-06 17:33:23 -0700893 * After the item has been detached from the filesystem view, we are
894 * ready to tear it out of the hierarchy. Notify the client before
895 * we do that so they can perform any cleanup that requires
896 * navigating the hierarchy. A client does not need to provide this
897 * callback. The subsystem semaphore MUST be held by the caller, and
898 * references must be valid for both items. It also assumes the
899 * caller has validated ci_type.
900 */
901static void client_disconnect_notify(struct config_item *parent_item,
902 struct config_item *item)
903{
904 struct config_item_type *type;
905
906 type = parent_item->ci_type;
907 BUG_ON(!type);
908
909 if (type->ct_group_ops && type->ct_group_ops->disconnect_notify)
910 type->ct_group_ops->disconnect_notify(to_config_group(parent_item),
911 item);
912}
913
914/*
Joel Becker7063fbf2005-12-15 14:29:43 -0800915 * Drop the initial reference from make_item()/make_group()
916 * This function assumes that reference is held on item
917 * and that item holds a valid reference to the parent. Also, it
918 * assumes the caller has validated ci_type.
919 */
920static void client_drop_item(struct config_item *parent_item,
921 struct config_item *item)
922{
923 struct config_item_type *type;
924
925 type = parent_item->ci_type;
926 BUG_ON(!type);
927
Joel Beckereed7a0d2006-04-11 21:37:20 -0700928 /*
929 * If ->drop_item() exists, it is responsible for the
930 * config_item_put().
931 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800932 if (type->ct_group_ops && type->ct_group_ops->drop_item)
933 type->ct_group_ops->drop_item(to_config_group(parent_item),
Joel Becker299894c2006-10-06 17:33:23 -0700934 item);
Joel Becker7063fbf2005-12-15 14:29:43 -0800935 else
936 config_item_put(item);
937}
938
Joel Becker631d1fe2007-06-18 18:06:09 -0700939#ifdef DEBUG
940static void configfs_dump_one(struct configfs_dirent *sd, int level)
941{
Fabian Frederickc6686932014-06-04 16:05:58 -0700942 pr_info("%*s\"%s\":\n", level, " ", configfs_get_name(sd));
Joel Becker631d1fe2007-06-18 18:06:09 -0700943
Fabian Frederickc6686932014-06-04 16:05:58 -0700944#define type_print(_type) if (sd->s_type & _type) pr_info("%*s %s\n", level, " ", #_type);
Joel Becker631d1fe2007-06-18 18:06:09 -0700945 type_print(CONFIGFS_ROOT);
946 type_print(CONFIGFS_DIR);
947 type_print(CONFIGFS_ITEM_ATTR);
948 type_print(CONFIGFS_ITEM_LINK);
949 type_print(CONFIGFS_USET_DIR);
950 type_print(CONFIGFS_USET_DEFAULT);
951 type_print(CONFIGFS_USET_DROPPING);
952#undef type_print
953}
954
955static int configfs_dump(struct configfs_dirent *sd, int level)
956{
957 struct configfs_dirent *child_sd;
958 int ret = 0;
959
960 configfs_dump_one(sd, level);
961
962 if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT)))
963 return 0;
964
965 list_for_each_entry(child_sd, &sd->s_children, s_sibling) {
966 ret = configfs_dump(child_sd, level + 2);
967 if (ret)
968 break;
969 }
970
971 return ret;
972}
973#endif
974
975
976/*
977 * configfs_depend_item() and configfs_undepend_item()
978 *
979 * WARNING: Do not call these from a configfs callback!
980 *
981 * This describes these functions and their helpers.
982 *
983 * Allow another kernel system to depend on a config_item. If this
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300984 * happens, the item cannot go away until the dependent can live without
Joel Becker631d1fe2007-06-18 18:06:09 -0700985 * it. The idea is to give client modules as simple an interface as
986 * possible. When a system asks them to depend on an item, they just
987 * call configfs_depend_item(). If the item is live and the client
988 * driver is in good shape, we'll happily do the work for them.
989 *
990 * Why is the locking complex? Because configfs uses the VFS to handle
991 * all locking, but this function is called outside the normal
992 * VFS->configfs path. So it must take VFS locks to prevent the
993 * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is
994 * why you can't call these functions underneath configfs callbacks.
995 *
996 * Note, btw, that this can be called at *any* time, even when a configfs
997 * subsystem isn't registered, or when configfs is loading or unloading.
998 * Just like configfs_register_subsystem(). So we take the same
Louis Rilling420118c2009-01-28 19:18:33 +0100999 * precautions. We pin the filesystem. We lock configfs_dirent_lock.
1000 * If we can find the target item in the
Joel Becker631d1fe2007-06-18 18:06:09 -07001001 * configfs tree, it must be part of the subsystem tree as well, so we
Louis Rilling420118c2009-01-28 19:18:33 +01001002 * do not need the subsystem semaphore. Holding configfs_dirent_lock helps
1003 * locking out mkdir() and rmdir(), who might be racing us.
Joel Becker631d1fe2007-06-18 18:06:09 -07001004 */
1005
1006/*
1007 * configfs_depend_prep()
1008 *
1009 * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are
1010 * attributes. This is similar but not the same to configfs_detach_prep().
1011 * Note that configfs_detach_prep() expects the parent to be locked when it
1012 * is called, but we lock the parent *inside* configfs_depend_prep(). We
1013 * do that so we can unlock it if we find nothing.
1014 *
1015 * Here we do a depth-first search of the dentry hierarchy looking for
Louis Rilling420118c2009-01-28 19:18:33 +01001016 * our object.
1017 * We deliberately ignore items tagged as dropping since they are virtually
1018 * dead, as well as items in the middle of attachment since they virtually
1019 * do not exist yet. This completes the locking out of racing mkdir() and
1020 * rmdir().
1021 * Note: subdirectories in the middle of attachment start with s_type =
1022 * CONFIGFS_DIR|CONFIGFS_USET_CREATING set by create_dir(). When
1023 * CONFIGFS_USET_CREATING is set, we ignore the item. The actual set of
1024 * s_type is in configfs_new_dirent(), which has configfs_dirent_lock.
Joel Becker631d1fe2007-06-18 18:06:09 -07001025 *
Louis Rilling420118c2009-01-28 19:18:33 +01001026 * If the target is not found, -ENOENT is bubbled up.
Joel Becker631d1fe2007-06-18 18:06:09 -07001027 *
1028 * This adds a requirement that all config_items be unique!
1029 *
Louis Rilling420118c2009-01-28 19:18:33 +01001030 * This is recursive. There isn't
Joel Becker631d1fe2007-06-18 18:06:09 -07001031 * much on the stack, though, so folks that need this function - be careful
1032 * about your stack! Patches will be accepted to make it iterative.
1033 */
1034static int configfs_depend_prep(struct dentry *origin,
1035 struct config_item *target)
1036{
Wei Yongjun49deb4b2013-02-21 16:42:43 -08001037 struct configfs_dirent *child_sd, *sd;
Joel Becker631d1fe2007-06-18 18:06:09 -07001038 int ret = 0;
1039
Wei Yongjun49deb4b2013-02-21 16:42:43 -08001040 BUG_ON(!origin || !origin->d_fsdata);
1041 sd = origin->d_fsdata;
Joel Becker631d1fe2007-06-18 18:06:09 -07001042
Joel Becker631d1fe2007-06-18 18:06:09 -07001043 if (sd->s_element == target) /* Boo-yah */
1044 goto out;
1045
1046 list_for_each_entry(child_sd, &sd->s_children, s_sibling) {
Louis Rilling420118c2009-01-28 19:18:33 +01001047 if ((child_sd->s_type & CONFIGFS_DIR) &&
1048 !(child_sd->s_type & CONFIGFS_USET_DROPPING) &&
1049 !(child_sd->s_type & CONFIGFS_USET_CREATING)) {
Joel Becker631d1fe2007-06-18 18:06:09 -07001050 ret = configfs_depend_prep(child_sd->s_dentry,
1051 target);
1052 if (!ret)
1053 goto out; /* Child path boo-yah */
1054 }
1055 }
1056
1057 /* We looped all our children and didn't find target */
Joel Becker631d1fe2007-06-18 18:06:09 -07001058 ret = -ENOENT;
1059
1060out:
1061 return ret;
1062}
1063
Krzysztof Opasiak9fb434e2015-12-11 16:06:10 +01001064static int configfs_do_depend_item(struct dentry *subsys_dentry,
1065 struct config_item *target)
1066{
1067 struct configfs_dirent *p;
1068 int ret;
1069
1070 spin_lock(&configfs_dirent_lock);
1071 /* Scan the tree, return 0 if found */
1072 ret = configfs_depend_prep(subsys_dentry, target);
1073 if (ret)
1074 goto out_unlock_dirent_lock;
1075
1076 /*
1077 * We are sure that the item is not about to be removed by rmdir(), and
1078 * not in the middle of attachment by mkdir().
1079 */
1080 p = target->ci_dentry->d_fsdata;
1081 p->s_dependent_count += 1;
1082
1083out_unlock_dirent_lock:
1084 spin_unlock(&configfs_dirent_lock);
1085
1086 return ret;
1087}
1088
Krzysztof Opasiak9a70adf2015-12-11 16:06:11 +01001089static inline struct configfs_dirent *
1090configfs_find_subsys_dentry(struct configfs_dirent *root_sd,
1091 struct config_item *subsys_item)
1092{
1093 struct configfs_dirent *p;
1094 struct configfs_dirent *ret = NULL;
1095
1096 list_for_each_entry(p, &root_sd->s_children, s_sibling) {
1097 if (p->s_type & CONFIGFS_DIR &&
1098 p->s_element == subsys_item) {
1099 ret = p;
1100 break;
1101 }
1102 }
1103
1104 return ret;
1105}
1106
1107
Joel Becker631d1fe2007-06-18 18:06:09 -07001108int configfs_depend_item(struct configfs_subsystem *subsys,
1109 struct config_item *target)
1110{
1111 int ret;
Krzysztof Opasiak9a70adf2015-12-11 16:06:11 +01001112 struct configfs_dirent *subsys_sd;
Joel Becker631d1fe2007-06-18 18:06:09 -07001113 struct config_item *s_item = &subsys->su_group.cg_item;
Al Virob7c177f2012-03-17 16:24:54 -04001114 struct dentry *root;
Joel Becker631d1fe2007-06-18 18:06:09 -07001115
1116 /*
1117 * Pin the configfs filesystem. This means we can safely access
1118 * the root of the configfs filesystem.
1119 */
Al Viro2a152ad2012-03-17 16:53:29 -04001120 root = configfs_pin_fs();
1121 if (IS_ERR(root))
1122 return PTR_ERR(root);
Joel Becker631d1fe2007-06-18 18:06:09 -07001123
1124 /*
1125 * Next, lock the root directory. We're going to check that the
1126 * subsystem is really registered, and so we need to lock out
1127 * configfs_[un]register_subsystem().
1128 */
Al Viro59551022016-01-22 15:40:57 -05001129 inode_lock(d_inode(root));
Joel Becker631d1fe2007-06-18 18:06:09 -07001130
Krzysztof Opasiak9a70adf2015-12-11 16:06:11 +01001131 subsys_sd = configfs_find_subsys_dentry(root->d_fsdata, s_item);
Joel Becker631d1fe2007-06-18 18:06:09 -07001132 if (!subsys_sd) {
1133 ret = -ENOENT;
1134 goto out_unlock_fs;
1135 }
1136
1137 /* Ok, now we can trust subsys/s_item */
Krzysztof Opasiak9fb434e2015-12-11 16:06:10 +01001138 ret = configfs_do_depend_item(subsys_sd->s_dentry, target);
Joel Becker631d1fe2007-06-18 18:06:09 -07001139
Joel Becker631d1fe2007-06-18 18:06:09 -07001140out_unlock_fs:
Al Viro59551022016-01-22 15:40:57 -05001141 inode_unlock(d_inode(root));
Joel Becker631d1fe2007-06-18 18:06:09 -07001142
1143 /*
1144 * If we succeeded, the fs is pinned via other methods. If not,
1145 * we're done with it anyway. So release_fs() is always right.
1146 */
1147 configfs_release_fs();
1148
1149 return ret;
1150}
1151EXPORT_SYMBOL(configfs_depend_item);
1152
1153/*
1154 * Release the dependent linkage. This is much simpler than
1155 * configfs_depend_item() because we know that that the client driver is
1156 * pinned, thus the subsystem is pinned, and therefore configfs is pinned.
1157 */
Krzysztof Opasiak9a9e3412015-12-11 16:06:09 +01001158void configfs_undepend_item(struct config_item *target)
Joel Becker631d1fe2007-06-18 18:06:09 -07001159{
1160 struct configfs_dirent *sd;
1161
1162 /*
Louis Rilling420118c2009-01-28 19:18:33 +01001163 * Since we can trust everything is pinned, we just need
1164 * configfs_dirent_lock.
Joel Becker631d1fe2007-06-18 18:06:09 -07001165 */
Louis Rilling420118c2009-01-28 19:18:33 +01001166 spin_lock(&configfs_dirent_lock);
Joel Becker631d1fe2007-06-18 18:06:09 -07001167
1168 sd = target->ci_dentry->d_fsdata;
1169 BUG_ON(sd->s_dependent_count < 1);
1170
1171 sd->s_dependent_count -= 1;
1172
1173 /*
1174 * After this unlock, we cannot trust the item to stay alive!
1175 * DO NOT REFERENCE item after this unlock.
1176 */
Louis Rilling420118c2009-01-28 19:18:33 +01001177 spin_unlock(&configfs_dirent_lock);
Joel Becker631d1fe2007-06-18 18:06:09 -07001178}
1179EXPORT_SYMBOL(configfs_undepend_item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001180
Krzysztof Opasiakd79d75b2015-12-11 16:06:12 +01001181/*
1182 * caller_subsys is a caller's subsystem not target's. This is used to
1183 * determine if we should lock root and check subsys or not. When we are
1184 * in the same subsystem as our target there is no need to do locking as
1185 * we know that subsys is valid and is not unregistered during this function
1186 * as we are called from callback of one of his children and VFS holds a lock
1187 * on some inode. Otherwise we have to lock our root to ensure that target's
1188 * subsystem it is not unregistered during this function.
1189 */
1190int configfs_depend_item_unlocked(struct configfs_subsystem *caller_subsys,
1191 struct config_item *target)
1192{
1193 struct configfs_subsystem *target_subsys;
1194 struct config_group *root, *parent;
1195 struct configfs_dirent *subsys_sd;
1196 int ret = -ENOENT;
1197
1198 /* Disallow this function for configfs root */
1199 if (configfs_is_root(target))
1200 return -EINVAL;
1201
1202 parent = target->ci_group;
1203 /*
1204 * This may happen when someone is trying to depend root
1205 * directory of some subsystem
1206 */
1207 if (configfs_is_root(&parent->cg_item)) {
1208 target_subsys = to_configfs_subsystem(to_config_group(target));
1209 root = parent;
1210 } else {
1211 target_subsys = parent->cg_subsys;
1212 /* Find a cofnigfs root as we may need it for locking */
1213 for (root = parent; !configfs_is_root(&root->cg_item);
1214 root = root->cg_item.ci_group)
1215 ;
1216 }
1217
1218 if (target_subsys != caller_subsys) {
1219 /*
1220 * We are in other configfs subsystem, so we have to do
1221 * additional locking to prevent other subsystem from being
1222 * unregistered
1223 */
Al Viro59551022016-01-22 15:40:57 -05001224 inode_lock(d_inode(root->cg_item.ci_dentry));
Krzysztof Opasiakd79d75b2015-12-11 16:06:12 +01001225
1226 /*
1227 * As we are trying to depend item from other subsystem
1228 * we have to check if this subsystem is still registered
1229 */
1230 subsys_sd = configfs_find_subsys_dentry(
1231 root->cg_item.ci_dentry->d_fsdata,
1232 &target_subsys->su_group.cg_item);
1233 if (!subsys_sd)
1234 goto out_root_unlock;
1235 } else {
1236 subsys_sd = target_subsys->su_group.cg_item.ci_dentry->d_fsdata;
1237 }
1238
1239 /* Now we can execute core of depend item */
1240 ret = configfs_do_depend_item(subsys_sd->s_dentry, target);
1241
1242 if (target_subsys != caller_subsys)
1243out_root_unlock:
1244 /*
1245 * We were called from subsystem other than our target so we
1246 * took some locks so now it's time to release them
1247 */
Al Viro59551022016-01-22 15:40:57 -05001248 inode_unlock(d_inode(root->cg_item.ci_dentry));
Krzysztof Opasiakd79d75b2015-12-11 16:06:12 +01001249
1250 return ret;
1251}
1252EXPORT_SYMBOL(configfs_depend_item_unlocked);
1253
Al Viro18bb1db2011-07-26 01:41:39 -04001254static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
Joel Becker7063fbf2005-12-15 14:29:43 -08001255{
Joel Beckera6795e92008-07-17 15:21:29 -07001256 int ret = 0;
1257 int module_got = 0;
1258 struct config_group *group = NULL;
1259 struct config_item *item = NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -08001260 struct config_item *parent_item;
1261 struct configfs_subsystem *subsys;
1262 struct configfs_dirent *sd;
1263 struct config_item_type *type;
Joel Becker70526b62008-06-17 15:34:32 -07001264 struct module *subsys_owner = NULL, *new_item_owner = NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -08001265 char *name;
1266
Joel Becker7063fbf2005-12-15 14:29:43 -08001267 sd = dentry->d_parent->d_fsdata;
Louis Rilling2a109f22008-07-04 16:56:05 +02001268
1269 /*
1270 * Fake invisibility if dir belongs to a group/default groups hierarchy
1271 * being attached
1272 */
1273 if (!configfs_dirent_is_ready(sd)) {
1274 ret = -ENOENT;
1275 goto out;
1276 }
1277
Joel Becker84efad12006-03-27 18:46:09 -08001278 if (!(sd->s_type & CONFIGFS_USET_DIR)) {
1279 ret = -EPERM;
1280 goto out;
1281 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001282
Joel Becker84efad12006-03-27 18:46:09 -08001283 /* Get a working ref for the duration of this function */
Joel Becker7063fbf2005-12-15 14:29:43 -08001284 parent_item = configfs_get_config_item(dentry->d_parent);
1285 type = parent_item->ci_type;
1286 subsys = to_config_group(parent_item)->cg_subsys;
1287 BUG_ON(!subsys);
1288
1289 if (!type || !type->ct_group_ops ||
1290 (!type->ct_group_ops->make_group &&
1291 !type->ct_group_ops->make_item)) {
Joel Becker84efad12006-03-27 18:46:09 -08001292 ret = -EPERM; /* Lack-of-mkdir returns -EPERM */
1293 goto out_put;
Joel Becker7063fbf2005-12-15 14:29:43 -08001294 }
1295
Joel Becker70526b62008-06-17 15:34:32 -07001296 /*
1297 * The subsystem may belong to a different module than the item
1298 * being created. We don't want to safely pin the new item but
1299 * fail to pin the subsystem it sits under.
1300 */
1301 if (!subsys->su_group.cg_item.ci_type) {
1302 ret = -EINVAL;
1303 goto out_put;
1304 }
1305 subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner;
1306 if (!try_module_get(subsys_owner)) {
1307 ret = -EINVAL;
1308 goto out_put;
1309 }
1310
Joel Becker7063fbf2005-12-15 14:29:43 -08001311 name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL);
1312 if (!name) {
Joel Becker84efad12006-03-27 18:46:09 -08001313 ret = -ENOMEM;
Joel Becker70526b62008-06-17 15:34:32 -07001314 goto out_subsys_put;
Joel Becker7063fbf2005-12-15 14:29:43 -08001315 }
Joel Becker84efad12006-03-27 18:46:09 -08001316
Joel Becker7063fbf2005-12-15 14:29:43 -08001317 snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name);
1318
Joel Beckere6bd07a2007-07-06 23:33:17 -07001319 mutex_lock(&subsys->su_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001320 if (type->ct_group_ops->make_group) {
Joel Beckerf89ab862008-07-17 14:53:48 -07001321 group = type->ct_group_ops->make_group(to_config_group(parent_item), name);
Joel Beckera6795e92008-07-17 15:21:29 -07001322 if (!group)
1323 group = ERR_PTR(-ENOMEM);
1324 if (!IS_ERR(group)) {
Joel Becker7063fbf2005-12-15 14:29:43 -08001325 link_group(to_config_group(parent_item), group);
1326 item = &group->cg_item;
Joel Beckera6795e92008-07-17 15:21:29 -07001327 } else
1328 ret = PTR_ERR(group);
Joel Becker7063fbf2005-12-15 14:29:43 -08001329 } else {
Joel Beckerf89ab862008-07-17 14:53:48 -07001330 item = type->ct_group_ops->make_item(to_config_group(parent_item), name);
Joel Beckera6795e92008-07-17 15:21:29 -07001331 if (!item)
1332 item = ERR_PTR(-ENOMEM);
1333 if (!IS_ERR(item))
Joel Becker7063fbf2005-12-15 14:29:43 -08001334 link_obj(parent_item, item);
Joel Beckera6795e92008-07-17 15:21:29 -07001335 else
1336 ret = PTR_ERR(item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001337 }
Joel Beckere6bd07a2007-07-06 23:33:17 -07001338 mutex_unlock(&subsys->su_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001339
1340 kfree(name);
Joel Beckera6795e92008-07-17 15:21:29 -07001341 if (ret) {
Joel Beckereed7a0d2006-04-11 21:37:20 -07001342 /*
Joel Beckerdacdd0e2008-07-17 16:54:19 -07001343 * If ret != 0, then link_obj() was never called.
Joel Beckereed7a0d2006-04-11 21:37:20 -07001344 * There are no extra references to clean up.
1345 */
Joel Becker70526b62008-06-17 15:34:32 -07001346 goto out_subsys_put;
Joel Becker7063fbf2005-12-15 14:29:43 -08001347 }
1348
Joel Beckereed7a0d2006-04-11 21:37:20 -07001349 /*
1350 * link_obj() has been called (via link_group() for groups).
1351 * From here on out, errors must clean that up.
1352 */
1353
Joel Becker7063fbf2005-12-15 14:29:43 -08001354 type = item->ci_type;
Joel Beckereed7a0d2006-04-11 21:37:20 -07001355 if (!type) {
1356 ret = -EINVAL;
1357 goto out_unlink;
1358 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001359
Joel Becker70526b62008-06-17 15:34:32 -07001360 new_item_owner = type->ct_owner;
1361 if (!try_module_get(new_item_owner)) {
Joel Beckereed7a0d2006-04-11 21:37:20 -07001362 ret = -EINVAL;
1363 goto out_unlink;
1364 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001365
Joel Beckereed7a0d2006-04-11 21:37:20 -07001366 /*
1367 * I hate doing it this way, but if there is
1368 * an error, module_put() probably should
1369 * happen after any cleanup.
1370 */
1371 module_got = 1;
1372
Louis Rilling6d8344b2008-06-16 19:01:02 +02001373 /*
1374 * Make racing rmdir() fail if it did not tag parent with
1375 * CONFIGFS_USET_DROPPING
1376 * Note: if CONFIGFS_USET_DROPPING is already set, attach_group() will
1377 * fail and let rmdir() terminate correctly
1378 */
1379 spin_lock(&configfs_dirent_lock);
1380 /* This will make configfs_detach_prep() fail */
1381 sd->s_type |= CONFIGFS_USET_IN_MKDIR;
1382 spin_unlock(&configfs_dirent_lock);
1383
Joel Beckereed7a0d2006-04-11 21:37:20 -07001384 if (group)
1385 ret = configfs_attach_group(parent_item, item, dentry);
1386 else
1387 ret = configfs_attach_item(parent_item, item, dentry);
1388
Louis Rilling6d8344b2008-06-16 19:01:02 +02001389 spin_lock(&configfs_dirent_lock);
1390 sd->s_type &= ~CONFIGFS_USET_IN_MKDIR;
Louis Rilling2a109f22008-07-04 16:56:05 +02001391 if (!ret)
1392 configfs_dir_set_ready(dentry->d_fsdata);
Louis Rilling6d8344b2008-06-16 19:01:02 +02001393 spin_unlock(&configfs_dirent_lock);
1394
Joel Beckereed7a0d2006-04-11 21:37:20 -07001395out_unlink:
1396 if (ret) {
1397 /* Tear down everything we built up */
Joel Beckere6bd07a2007-07-06 23:33:17 -07001398 mutex_lock(&subsys->su_mutex);
Joel Becker299894c2006-10-06 17:33:23 -07001399
1400 client_disconnect_notify(parent_item, item);
Joel Beckereed7a0d2006-04-11 21:37:20 -07001401 if (group)
1402 unlink_group(group);
1403 else
1404 unlink_obj(item);
1405 client_drop_item(parent_item, item);
Joel Becker299894c2006-10-06 17:33:23 -07001406
Joel Beckere6bd07a2007-07-06 23:33:17 -07001407 mutex_unlock(&subsys->su_mutex);
Joel Beckereed7a0d2006-04-11 21:37:20 -07001408
1409 if (module_got)
Joel Becker70526b62008-06-17 15:34:32 -07001410 module_put(new_item_owner);
Joel Becker7063fbf2005-12-15 14:29:43 -08001411 }
1412
Joel Becker70526b62008-06-17 15:34:32 -07001413out_subsys_put:
1414 if (ret)
1415 module_put(subsys_owner);
1416
Joel Becker84efad12006-03-27 18:46:09 -08001417out_put:
1418 /*
Joel Beckereed7a0d2006-04-11 21:37:20 -07001419 * link_obj()/link_group() took a reference from child->parent,
1420 * so the parent is safely pinned. We can drop our working
1421 * reference.
Joel Becker84efad12006-03-27 18:46:09 -08001422 */
1423 config_item_put(parent_item);
1424
1425out:
Joel Becker7063fbf2005-12-15 14:29:43 -08001426 return ret;
1427}
1428
1429static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
1430{
1431 struct config_item *parent_item;
1432 struct config_item *item;
1433 struct configfs_subsystem *subsys;
1434 struct configfs_dirent *sd;
Joel Becker70526b62008-06-17 15:34:32 -07001435 struct module *subsys_owner = NULL, *dead_item_owner = NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -08001436 int ret;
1437
Joel Becker7063fbf2005-12-15 14:29:43 -08001438 sd = dentry->d_fsdata;
1439 if (sd->s_type & CONFIGFS_USET_DEFAULT)
1440 return -EPERM;
1441
Joel Becker84efad12006-03-27 18:46:09 -08001442 /* Get a working ref until we have the child */
Joel Becker7063fbf2005-12-15 14:29:43 -08001443 parent_item = configfs_get_config_item(dentry->d_parent);
1444 subsys = to_config_group(parent_item)->cg_subsys;
1445 BUG_ON(!subsys);
1446
1447 if (!parent_item->ci_type) {
1448 config_item_put(parent_item);
1449 return -EINVAL;
1450 }
1451
Joel Becker70526b62008-06-17 15:34:32 -07001452 /* configfs_mkdir() shouldn't have allowed this */
1453 BUG_ON(!subsys->su_group.cg_item.ci_type);
1454 subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner;
1455
Louis Rilling9a73d782008-06-20 14:09:22 +02001456 /*
1457 * Ensure that no racing symlink() will make detach_prep() fail while
1458 * the new link is temporarily attached
1459 */
Louis Rilling6d8344b2008-06-16 19:01:02 +02001460 do {
Al Viro48f35b72016-04-12 00:37:59 -04001461 struct dentry *wait;
Louis Rilling6d8344b2008-06-16 19:01:02 +02001462
Louis Rillingde6bf182008-08-15 12:37:23 -07001463 mutex_lock(&configfs_symlink_mutex);
1464 spin_lock(&configfs_dirent_lock);
Louis Rilling420118c2009-01-28 19:18:33 +01001465 /*
1466 * Here's where we check for dependents. We're protected by
1467 * configfs_dirent_lock.
1468 * If no dependent, atomically tag the item as dropping.
1469 */
1470 ret = sd->s_dependent_count ? -EBUSY : 0;
1471 if (!ret) {
Al Viro48f35b72016-04-12 00:37:59 -04001472 ret = configfs_detach_prep(dentry, &wait);
Louis Rilling420118c2009-01-28 19:18:33 +01001473 if (ret)
1474 configfs_detach_rollback(dentry);
1475 }
Louis Rillingde6bf182008-08-15 12:37:23 -07001476 spin_unlock(&configfs_dirent_lock);
1477 mutex_unlock(&configfs_symlink_mutex);
1478
1479 if (ret) {
Louis Rilling6d8344b2008-06-16 19:01:02 +02001480 if (ret != -EAGAIN) {
1481 config_item_put(parent_item);
1482 return ret;
1483 }
1484
1485 /* Wait until the racing operation terminates */
Al Viro48f35b72016-04-12 00:37:59 -04001486 inode_lock(d_inode(wait));
1487 inode_unlock(d_inode(wait));
1488 dput(wait);
Louis Rilling6d8344b2008-06-16 19:01:02 +02001489 }
1490 } while (ret == -EAGAIN);
Joel Becker7063fbf2005-12-15 14:29:43 -08001491
Joel Becker84efad12006-03-27 18:46:09 -08001492 /* Get a working ref for the duration of this function */
Joel Becker7063fbf2005-12-15 14:29:43 -08001493 item = configfs_get_config_item(dentry);
1494
1495 /* Drop reference from above, item already holds one. */
1496 config_item_put(parent_item);
1497
1498 if (item->ci_type)
Joel Becker70526b62008-06-17 15:34:32 -07001499 dead_item_owner = item->ci_type->ct_owner;
Joel Becker7063fbf2005-12-15 14:29:43 -08001500
1501 if (sd->s_type & CONFIGFS_USET_DIR) {
1502 configfs_detach_group(item);
1503
Joel Beckere6bd07a2007-07-06 23:33:17 -07001504 mutex_lock(&subsys->su_mutex);
Joel Becker299894c2006-10-06 17:33:23 -07001505 client_disconnect_notify(parent_item, item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001506 unlink_group(to_config_group(item));
1507 } else {
1508 configfs_detach_item(item);
1509
Joel Beckere6bd07a2007-07-06 23:33:17 -07001510 mutex_lock(&subsys->su_mutex);
Joel Becker299894c2006-10-06 17:33:23 -07001511 client_disconnect_notify(parent_item, item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001512 unlink_obj(item);
1513 }
1514
1515 client_drop_item(parent_item, item);
Joel Beckere6bd07a2007-07-06 23:33:17 -07001516 mutex_unlock(&subsys->su_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001517
1518 /* Drop our reference from above */
1519 config_item_put(item);
1520
Joel Becker70526b62008-06-17 15:34:32 -07001521 module_put(dead_item_owner);
1522 module_put(subsys_owner);
Joel Becker7063fbf2005-12-15 14:29:43 -08001523
1524 return 0;
1525}
1526
Arjan van de Ven754661f2007-02-12 00:55:38 -08001527const struct inode_operations configfs_dir_inode_operations = {
Joel Becker7063fbf2005-12-15 14:29:43 -08001528 .mkdir = configfs_mkdir,
1529 .rmdir = configfs_rmdir,
1530 .symlink = configfs_symlink,
1531 .unlink = configfs_unlink,
1532 .lookup = configfs_lookup,
Joel Becker3d0f89b2006-01-25 13:31:07 -08001533 .setattr = configfs_setattr,
Joel Becker7063fbf2005-12-15 14:29:43 -08001534};
1535
Al Viro81d44ed12012-03-17 16:13:25 -04001536const struct inode_operations configfs_root_inode_operations = {
1537 .lookup = configfs_lookup,
1538 .setattr = configfs_setattr,
1539};
1540
Joel Becker7063fbf2005-12-15 14:29:43 -08001541#if 0
1542int configfs_rename_dir(struct config_item * item, const char *new_name)
1543{
1544 int error = 0;
1545 struct dentry * new_dentry, * parent;
1546
1547 if (!strcmp(config_item_name(item), new_name))
1548 return -EINVAL;
1549
1550 if (!item->parent)
1551 return -EINVAL;
1552
1553 down_write(&configfs_rename_sem);
1554 parent = item->parent->dentry;
1555
Al Viro59551022016-01-22 15:40:57 -05001556 inode_lock(d_inode(parent));
Joel Becker7063fbf2005-12-15 14:29:43 -08001557
1558 new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
1559 if (!IS_ERR(new_dentry)) {
David Howells2b0143b2015-03-17 22:25:59 +00001560 if (d_really_is_negative(new_dentry)) {
Joel Becker7063fbf2005-12-15 14:29:43 -08001561 error = config_item_set_name(item, "%s", new_name);
1562 if (!error) {
1563 d_add(new_dentry, NULL);
1564 d_move(item->dentry, new_dentry);
1565 }
1566 else
1567 d_delete(new_dentry);
1568 } else
1569 error = -EEXIST;
1570 dput(new_dentry);
1571 }
Al Viro59551022016-01-22 15:40:57 -05001572 inode_unlock(d_inode(parent));
Joel Becker7063fbf2005-12-15 14:29:43 -08001573 up_write(&configfs_rename_sem);
1574
1575 return error;
1576}
1577#endif
1578
1579static int configfs_dir_open(struct inode *inode, struct file *file)
1580{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001581 struct dentry * dentry = file->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001582 struct configfs_dirent * parent_sd = dentry->d_fsdata;
Louis Rilling2a109f22008-07-04 16:56:05 +02001583 int err;
Joel Becker7063fbf2005-12-15 14:29:43 -08001584
Al Viro59551022016-01-22 15:40:57 -05001585 inode_lock(d_inode(dentry));
Louis Rilling2a109f22008-07-04 16:56:05 +02001586 /*
1587 * Fake invisibility if dir belongs to a group/default groups hierarchy
1588 * being attached
1589 */
1590 err = -ENOENT;
1591 if (configfs_dirent_is_ready(parent_sd)) {
Louis Rilling420118c2009-01-28 19:18:33 +01001592 file->private_data = configfs_new_dirent(parent_sd, NULL, 0);
Louis Rilling2a109f22008-07-04 16:56:05 +02001593 if (IS_ERR(file->private_data))
1594 err = PTR_ERR(file->private_data);
1595 else
1596 err = 0;
1597 }
Al Viro59551022016-01-22 15:40:57 -05001598 inode_unlock(d_inode(dentry));
Joel Becker7063fbf2005-12-15 14:29:43 -08001599
Louis Rilling2a109f22008-07-04 16:56:05 +02001600 return err;
Joel Becker7063fbf2005-12-15 14:29:43 -08001601}
1602
1603static int configfs_dir_close(struct inode *inode, struct file *file)
1604{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001605 struct dentry * dentry = file->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001606 struct configfs_dirent * cursor = file->private_data;
1607
Al Viro59551022016-01-22 15:40:57 -05001608 inode_lock(d_inode(dentry));
Louis Rilling6f610762008-06-16 19:00:58 +02001609 spin_lock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001610 list_del_init(&cursor->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +02001611 spin_unlock(&configfs_dirent_lock);
Al Viro59551022016-01-22 15:40:57 -05001612 inode_unlock(d_inode(dentry));
Joel Becker7063fbf2005-12-15 14:29:43 -08001613
1614 release_configfs_dirent(cursor);
1615
1616 return 0;
1617}
1618
1619/* Relationship between s_mode and the DT_xxx types */
1620static inline unsigned char dt_type(struct configfs_dirent *sd)
1621{
1622 return (sd->s_mode >> 12) & 15;
1623}
1624
Al Viro52018852013-05-16 01:28:34 -04001625static int configfs_readdir(struct file *file, struct dir_context *ctx)
Joel Becker7063fbf2005-12-15 14:29:43 -08001626{
Al Viro52018852013-05-16 01:28:34 -04001627 struct dentry *dentry = file->f_path.dentry;
Al Virob7c177f2012-03-17 16:24:54 -04001628 struct super_block *sb = dentry->d_sb;
Joel Becker7063fbf2005-12-15 14:29:43 -08001629 struct configfs_dirent * parent_sd = dentry->d_fsdata;
Al Viro52018852013-05-16 01:28:34 -04001630 struct configfs_dirent *cursor = file->private_data;
Joel Becker7063fbf2005-12-15 14:29:43 -08001631 struct list_head *p, *q = &cursor->s_sibling;
Joel Becker24307aa2011-05-18 04:08:16 -07001632 ino_t ino = 0;
Joel Becker7063fbf2005-12-15 14:29:43 -08001633
Al Viro52018852013-05-16 01:28:34 -04001634 if (!dir_emit_dots(file, ctx))
1635 return 0;
Al Viroa01b3002016-04-20 19:50:05 -04001636 spin_lock(&configfs_dirent_lock);
1637 if (ctx->pos == 2)
Al Viro52018852013-05-16 01:28:34 -04001638 list_move(q, &parent_sd->s_children);
Al Viro52018852013-05-16 01:28:34 -04001639 for (p = q->next; p != &parent_sd->s_children; p = p->next) {
1640 struct configfs_dirent *next;
1641 const char *name;
1642 int len;
1643 struct inode *inode = NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -08001644
Al Viro52018852013-05-16 01:28:34 -04001645 next = list_entry(p, struct configfs_dirent, s_sibling);
1646 if (!next->s_element)
1647 continue;
Joel Becker7063fbf2005-12-15 14:29:43 -08001648
Al Viro52018852013-05-16 01:28:34 -04001649 /*
1650 * We'll have a dentry and an inode for
1651 * PINNED items and for open attribute
1652 * files. We lock here to prevent a race
1653 * with configfs_d_iput() clearing
1654 * s_dentry before calling iput().
1655 *
1656 * Why do we go to the trouble? If
1657 * someone has an attribute file open,
1658 * the inode number should match until
1659 * they close it. Beyond that, we don't
1660 * care.
1661 */
Al Viro52018852013-05-16 01:28:34 -04001662 dentry = next->s_dentry;
1663 if (dentry)
David Howells2b0143b2015-03-17 22:25:59 +00001664 inode = d_inode(dentry);
Al Viro52018852013-05-16 01:28:34 -04001665 if (inode)
1666 ino = inode->i_ino;
1667 spin_unlock(&configfs_dirent_lock);
1668 if (!inode)
1669 ino = iunique(sb, 2);
Joel Becker7063fbf2005-12-15 14:29:43 -08001670
Al Viroa01b3002016-04-20 19:50:05 -04001671 name = configfs_get_name(next);
1672 len = strlen(name);
1673
Al Viro52018852013-05-16 01:28:34 -04001674 if (!dir_emit(ctx, name, len, ino, dt_type(next)))
1675 return 0;
Joel Becker7063fbf2005-12-15 14:29:43 -08001676
Al Viro52018852013-05-16 01:28:34 -04001677 spin_lock(&configfs_dirent_lock);
1678 list_move(q, p);
Al Viro52018852013-05-16 01:28:34 -04001679 p = q;
1680 ctx->pos++;
Joel Becker7063fbf2005-12-15 14:29:43 -08001681 }
Al Viroa01b3002016-04-20 19:50:05 -04001682 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001683 return 0;
1684}
1685
Andrew Morton965c8e52012-12-17 15:59:39 -08001686static loff_t configfs_dir_lseek(struct file *file, loff_t offset, int whence)
Joel Becker7063fbf2005-12-15 14:29:43 -08001687{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001688 struct dentry * dentry = file->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001689
Andrew Morton965c8e52012-12-17 15:59:39 -08001690 switch (whence) {
Joel Becker7063fbf2005-12-15 14:29:43 -08001691 case 1:
1692 offset += file->f_pos;
1693 case 0:
1694 if (offset >= 0)
1695 break;
1696 default:
Joel Becker7063fbf2005-12-15 14:29:43 -08001697 return -EINVAL;
1698 }
1699 if (offset != file->f_pos) {
1700 file->f_pos = offset;
1701 if (file->f_pos >= 2) {
1702 struct configfs_dirent *sd = dentry->d_fsdata;
1703 struct configfs_dirent *cursor = file->private_data;
1704 struct list_head *p;
1705 loff_t n = file->f_pos - 2;
1706
Louis Rilling6f610762008-06-16 19:00:58 +02001707 spin_lock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001708 list_del(&cursor->s_sibling);
1709 p = sd->s_children.next;
1710 while (n && p != &sd->s_children) {
1711 struct configfs_dirent *next;
1712 next = list_entry(p, struct configfs_dirent,
1713 s_sibling);
1714 if (next->s_element)
1715 n--;
1716 p = p->next;
1717 }
1718 list_add_tail(&cursor->s_sibling, p);
Louis Rilling6f610762008-06-16 19:00:58 +02001719 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001720 }
1721 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001722 return offset;
1723}
1724
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -08001725const struct file_operations configfs_dir_operations = {
Joel Becker7063fbf2005-12-15 14:29:43 -08001726 .open = configfs_dir_open,
1727 .release = configfs_dir_close,
1728 .llseek = configfs_dir_lseek,
1729 .read = generic_read_dir,
Al Viroa01b3002016-04-20 19:50:05 -04001730 .iterate_shared = configfs_readdir,
Joel Becker7063fbf2005-12-15 14:29:43 -08001731};
1732
Daniel Baluta5cf6a512015-11-20 15:56:53 -08001733/**
1734 * configfs_register_group - creates a parent-child relation between two groups
1735 * @parent_group: parent group
1736 * @group: child group
1737 *
1738 * link groups, creates dentry for the child and attaches it to the
1739 * parent dentry.
1740 *
1741 * Return: 0 on success, negative errno code on error
1742 */
1743int configfs_register_group(struct config_group *parent_group,
1744 struct config_group *group)
1745{
1746 struct configfs_subsystem *subsys = parent_group->cg_subsys;
1747 struct dentry *parent;
1748 int ret;
1749
1750 mutex_lock(&subsys->su_mutex);
1751 link_group(parent_group, group);
1752 mutex_unlock(&subsys->su_mutex);
1753
1754 parent = parent_group->cg_item.ci_dentry;
1755
Al Viro59551022016-01-22 15:40:57 -05001756 inode_lock_nested(d_inode(parent), I_MUTEX_PARENT);
Daniel Baluta5cf6a512015-11-20 15:56:53 -08001757 ret = create_default_group(parent_group, group);
1758 if (!ret) {
1759 spin_lock(&configfs_dirent_lock);
1760 configfs_dir_set_ready(group->cg_item.ci_dentry->d_fsdata);
1761 spin_unlock(&configfs_dirent_lock);
1762 }
Al Viro59551022016-01-22 15:40:57 -05001763 inode_unlock(d_inode(parent));
Daniel Baluta5cf6a512015-11-20 15:56:53 -08001764 return ret;
1765}
1766EXPORT_SYMBOL(configfs_register_group);
1767
1768/**
1769 * configfs_unregister_group() - unregisters a child group from its parent
1770 * @group: parent group to be unregistered
1771 *
1772 * Undoes configfs_register_group()
1773 */
1774void configfs_unregister_group(struct config_group *group)
1775{
1776 struct configfs_subsystem *subsys = group->cg_subsys;
1777 struct dentry *dentry = group->cg_item.ci_dentry;
1778 struct dentry *parent = group->cg_item.ci_parent->ci_dentry;
1779
Al Viro59551022016-01-22 15:40:57 -05001780 inode_lock_nested(d_inode(parent), I_MUTEX_PARENT);
Daniel Baluta5cf6a512015-11-20 15:56:53 -08001781 spin_lock(&configfs_dirent_lock);
1782 configfs_detach_prep(dentry, NULL);
1783 spin_unlock(&configfs_dirent_lock);
1784
1785 configfs_detach_group(&group->cg_item);
1786 d_inode(dentry)->i_flags |= S_DEAD;
1787 dont_mount(dentry);
1788 d_delete(dentry);
Al Viro59551022016-01-22 15:40:57 -05001789 inode_unlock(d_inode(parent));
Daniel Baluta5cf6a512015-11-20 15:56:53 -08001790
1791 dput(dentry);
1792
1793 mutex_lock(&subsys->su_mutex);
1794 unlink_group(group);
1795 mutex_unlock(&subsys->su_mutex);
1796}
1797EXPORT_SYMBOL(configfs_unregister_group);
1798
1799/**
1800 * configfs_register_default_group() - allocates and registers a child group
1801 * @parent_group: parent group
1802 * @name: child group name
1803 * @item_type: child item type description
1804 *
1805 * boilerplate to allocate and register a child group with its parent. We need
1806 * kzalloc'ed memory because child's default_group is initially empty.
1807 *
1808 * Return: allocated config group or ERR_PTR() on error
1809 */
1810struct config_group *
1811configfs_register_default_group(struct config_group *parent_group,
1812 const char *name,
1813 struct config_item_type *item_type)
1814{
1815 int ret;
1816 struct config_group *group;
1817
1818 group = kzalloc(sizeof(*group), GFP_KERNEL);
1819 if (!group)
1820 return ERR_PTR(-ENOMEM);
1821 config_group_init_type_name(group, name, item_type);
1822
1823 ret = configfs_register_group(parent_group, group);
1824 if (ret) {
1825 kfree(group);
1826 return ERR_PTR(ret);
1827 }
1828 return group;
1829}
1830EXPORT_SYMBOL(configfs_register_default_group);
1831
1832/**
1833 * configfs_unregister_default_group() - unregisters and frees a child group
1834 * @group: the group to act on
1835 */
1836void configfs_unregister_default_group(struct config_group *group)
1837{
1838 configfs_unregister_group(group);
1839 kfree(group);
1840}
1841EXPORT_SYMBOL(configfs_unregister_default_group);
1842
Joel Becker7063fbf2005-12-15 14:29:43 -08001843int configfs_register_subsystem(struct configfs_subsystem *subsys)
1844{
1845 int err;
1846 struct config_group *group = &subsys->su_group;
Joel Becker7063fbf2005-12-15 14:29:43 -08001847 struct dentry *dentry;
Al Virob7c177f2012-03-17 16:24:54 -04001848 struct dentry *root;
Joel Becker7063fbf2005-12-15 14:29:43 -08001849 struct configfs_dirent *sd;
1850
Al Viro2a152ad2012-03-17 16:53:29 -04001851 root = configfs_pin_fs();
1852 if (IS_ERR(root))
1853 return PTR_ERR(root);
Joel Becker7063fbf2005-12-15 14:29:43 -08001854
1855 if (!group->cg_item.ci_name)
1856 group->cg_item.ci_name = group->cg_item.ci_namebuf;
1857
Al Virob7c177f2012-03-17 16:24:54 -04001858 sd = root->d_fsdata;
Joel Becker7063fbf2005-12-15 14:29:43 -08001859 link_group(to_config_group(sd->s_element), group);
1860
Al Viro59551022016-01-22 15:40:57 -05001861 inode_lock_nested(d_inode(root), I_MUTEX_PARENT);
Joel Becker7063fbf2005-12-15 14:29:43 -08001862
Joel Becker7063fbf2005-12-15 14:29:43 -08001863 err = -ENOMEM;
Al Viroec193cf2013-07-14 17:16:52 +04001864 dentry = d_alloc_name(root, group->cg_item.ci_name);
Joel Beckerafdf04e2007-03-05 15:49:49 -08001865 if (dentry) {
1866 d_add(dentry, NULL);
Joel Becker7063fbf2005-12-15 14:29:43 -08001867
Joel Beckerafdf04e2007-03-05 15:49:49 -08001868 err = configfs_attach_group(sd->s_element, &group->cg_item,
1869 dentry);
1870 if (err) {
David Howells2b0143b2015-03-17 22:25:59 +00001871 BUG_ON(d_inode(dentry));
Joel Beckerdf7f9962011-02-22 01:09:49 -08001872 d_drop(dentry);
Joel Beckerafdf04e2007-03-05 15:49:49 -08001873 dput(dentry);
Louis Rilling2a109f22008-07-04 16:56:05 +02001874 } else {
1875 spin_lock(&configfs_dirent_lock);
1876 configfs_dir_set_ready(dentry->d_fsdata);
1877 spin_unlock(&configfs_dirent_lock);
Joel Beckerafdf04e2007-03-05 15:49:49 -08001878 }
1879 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001880
Al Viro59551022016-01-22 15:40:57 -05001881 inode_unlock(d_inode(root));
Joel Becker7063fbf2005-12-15 14:29:43 -08001882
Joel Beckerafdf04e2007-03-05 15:49:49 -08001883 if (err) {
1884 unlink_group(group);
1885 configfs_release_fs();
Joel Becker7063fbf2005-12-15 14:29:43 -08001886 }
1887
1888 return err;
1889}
1890
1891void configfs_unregister_subsystem(struct configfs_subsystem *subsys)
1892{
1893 struct config_group *group = &subsys->su_group;
1894 struct dentry *dentry = group->cg_item.ci_dentry;
Al Virob7c177f2012-03-17 16:24:54 -04001895 struct dentry *root = dentry->d_sb->s_root;
Joel Becker7063fbf2005-12-15 14:29:43 -08001896
Al Virob7c177f2012-03-17 16:24:54 -04001897 if (dentry->d_parent != root) {
Fabian Frederick1d88aa42014-06-04 16:05:59 -07001898 pr_err("Tried to unregister non-subsystem!\n");
Joel Becker7063fbf2005-12-15 14:29:43 -08001899 return;
1900 }
1901
Al Viro59551022016-01-22 15:40:57 -05001902 inode_lock_nested(d_inode(root),
Mark Fasheh55ed1602006-10-20 14:55:54 -07001903 I_MUTEX_PARENT);
Al Viro59551022016-01-22 15:40:57 -05001904 inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
Louis Rilling9a73d782008-06-20 14:09:22 +02001905 mutex_lock(&configfs_symlink_mutex);
Louis Rillingb3e76af2008-06-16 19:01:01 +02001906 spin_lock(&configfs_dirent_lock);
Louis Rilling6d8344b2008-06-16 19:01:02 +02001907 if (configfs_detach_prep(dentry, NULL)) {
Fabian Frederick1d88aa42014-06-04 16:05:59 -07001908 pr_err("Tried to unregister non-empty subsystem!\n");
Joel Becker7063fbf2005-12-15 14:29:43 -08001909 }
Louis Rillingb3e76af2008-06-16 19:01:01 +02001910 spin_unlock(&configfs_dirent_lock);
Louis Rilling9a73d782008-06-20 14:09:22 +02001911 mutex_unlock(&configfs_symlink_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001912 configfs_detach_group(&group->cg_item);
David Howells2b0143b2015-03-17 22:25:59 +00001913 d_inode(dentry)->i_flags |= S_DEAD;
Al Virod83c49f2010-04-30 17:17:09 -04001914 dont_mount(dentry);
Al Viro59551022016-01-22 15:40:57 -05001915 inode_unlock(d_inode(dentry));
Joel Becker7063fbf2005-12-15 14:29:43 -08001916
1917 d_delete(dentry);
1918
Al Viro59551022016-01-22 15:40:57 -05001919 inode_unlock(d_inode(root));
Joel Becker7063fbf2005-12-15 14:29:43 -08001920
1921 dput(dentry);
1922
1923 unlink_group(group);
1924 configfs_release_fs();
1925}
1926
1927EXPORT_SYMBOL(configfs_register_subsystem);
1928EXPORT_SYMBOL(configfs_unregister_subsystem);